Hardness testing machine



Sept; 9, 1947.

HARDNESS TESTING MACHINE Filed Oct. 15, 1945 3 Sheets-Sheet 1 I I l I 1 I lSnnentor v attorney! D. E. MICK -2,421,151

D. E. MICK 2,427,151

J'IARDNESS TESTING MACHINE I Filed Oct; 15, 1945 s Sheets-Shut 2 3 Sheets-Sheet 3 \r g A D. E. MICK HARDNE SS TESTING MACHINE Filed Oct. 15, 1945- K v4.1, mwmwZW 74 V fi///////////////// fi l/07 I I... I: n r

7 m w m m 1. v 7 #n f q v v Patented Sept. 9, 1947 HARDNE'SS TESTING; MACHINE f Douglas E. Mick, Jonesville,- Mich, assignor to Q General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application October 15, 1945, Serial No. 622,393

4 Claims. (01. 73-49) This invention relates generally to apparatus for testing the hardness of materials and more particularly to an improved machine for rapidly and accurately testing the hardness of metals of the type in which the hardness of the metal is determined by the height to which a hammer willrebound after striking the object to be tested.

One object of the invention is to provide an improved hardness testing machine which is accurate and more rapid in its operation than common hardness testing machines.

Another object of the invention is to provide an improved hardness testing machine that is more rapid in operation than common hardness testing machines and at the same time is simple in its construction and does not require frequent overhauling.

It is also an object of the invention to provide an improved hardness testing machine that can be readily adjusted to accommodate different sizes and shapes of parts to be tested.

A further object of the invention is to provide an improved hardness testing machine in which both hands of the operator are free to insert and remove work being tested.

Other objects and advantages of the invention will become more apparent from the detailed description which follows. Reference is herewith made to the accompanying drawings illustrating an apparatus constructed in accordance with one embodiment of the invention.

In the drawings:

Figure 1 is a side elevational view of the complete machine.

Figure 2 is a front elevational view of the machine illustrated in Figure l.

- Figure 3 is an enlarged view of a portion of the apparatus of Fig. 1, parts being shown in section to illustrate the construction more clearly.

Figure 4 is a top plan view of a portion of the apparatus with parts broken away-and in section to illustrate the construction more clearly.

Figure 5 is a partial sectional view illustratingwan arrangement of needle valves for controlling air flow to operating elements of the machine.

figure :6 is .a longitudinal sectional view through aJ-movable, portion of the apparatus adapted to be moved'to clamp the work to be. tested to :a work support or anvil and. carrying a hammer adapted when released to strike the work- In this figure the parts are shown in their up pcsitionsspri'orlto the start of a. cycle .ofioperation ferent sizes and shapes.

Figure 7 is a sectional view substantially on line 1-1 in Figure 8, parts being shown in their up positions prior to starting a cycle of operation.

Figure 8 is a sectional view of a view substantially on line 8-8 in Figure '7.

In the drawings, l0 indicates a base member having a removable work-supporting anvil II and an upwardly extending post or column l2. A head or bracket l4 carrying operating parts of the machine is adjustably mounted on the,

column l2 in order to accommodate work of dif- When in proper position for a part of particular dimensions the bracket I4 is fixed to the column by means of a hand wheel 16 which tightens a split-ring portion I8 of the bracket to the column (see especially Figure 4). In Figures 1 and 2 the base ll) of the machine is shown as supported by a bench or table 20. Suspended from the table by springs 22 is a four-way valve indicated generally at 24. Below the table is a valve 26 adapted to be operated by foot of the operator to control the operation of the four-way valve 24. These valves control air flow which actuate movable parts of the hardness testing machine as later described in detail.

Referring especially to Figure 3 (see also Figures l, 2 and 4) thereis shown a cylinder 30 supported by a hollow column portion I5 of the head or bracket l4. Within the cylinder is a piston 32, which is movable in one direction by air pressure supplied by pipe 34 and in the opposite direction by air pressure supplied by pipe 36. A rod 38 has one end fixed to the piston for movement thereby. The rod 38 extends downwardly through the hollow column l5 :into and through the smaller bore of a bushing 44. In the larger bore of the bushing 44 is a cap 40 fixed to the lower end of the rod in any suitable manner as for example, by acap' screw (not shown). A c011a,r l6 is adjustably securedto the rod 38; Surrounding the rod between the collar and the upper end of the bushingv M is a helical spring 48. Downward movement of the piston and rod 38 will compress the spring 48 and move the ,bushing downwardly within the hollowcolumn IS. The enlarged cap Ill provides a positive return of the bushingto the position shown in Figure 3 upon 1 upward movement of the rod 38. o

Fixed to the bushing for-movement therewith is a hangerSlLthe hollow columnii being cut away at oneside-to permit the hanger to extend therethrough and be movable therein. Carried by the-hanger is a tubular body 2 having a nose cap 54 removably secured thereto by screws 58. The nose cap of the tubular body when moved downward, clamps the work or part to be tested to the anvil during the testing operation. Screws 5'I secure the bushing, hanger and tubular body 52 to one another.

Fixed to the tubular body 52 and movable thereby is a small cylinder 58 having a piston 80 therein. A flexible air line 82 is connected to the cylinder 58 above the piston '80 for moving the latter in a downward direction while a flexible air line 84 is connected to the cylinder 58 below the piston for moving the same in the opposite direction. A rod 88 is connected at one end to the piston 80, and its other end is conin cylinder 58. The upper end portion of the clutch sleeve is tapered outwardly at I8 to form a cone surface. The clutch sleeve also is slotted at 11.

Within the clutch sleeve I4 is another sleeve 18, the upper end portion of which has a plurality of similar slotted portions 80 within which are similar steel balls 82 which in the position shown in Figure 8 contact the tapered portion of the clutch sleeve. Sleeve I8 is also slotted at 84. Between the lower end of the clutch sleeve I4 and sleeve I8 is a friction spring 88. A screw 88 in threaded engagement with the clutch sleeve is movable in an opening 80 in the sleev I8 (see Figure 6). Within the lower end of the sleeve 18 is a pilot sleeve 82 to which is flxed a latch 84. The pilot sleeve has an internal flan e 88 which in the position shown in Figure 'l is in en.-

gagement with andsuppor-ts an elongated hammer 98 having a point or tip I00 for engaging the part to be tested. This tip is preferably a diamond point. In the position shown in Figure 7 the steel balls-82 are pressed into contact with the hammer by the camming action of the cone surface I8. I

The lower end of sleeve I8 has threaded thereto'a ring I 02 having an inwardly extendin flange I04 acting as a stop for a pilot sleeve 92. In Figure 7 there is shown a trigger I08 pivoted at I08 to the tubular body 52 and movable i a slot I08 therein. -The trigger has a dog H0 in latching engagement with the latch 94 in the position shown in Figure 7. The trigger also has finger II2 adjacent the upper end thereof. A leafspring H4 is shown biasing the trigger to the right in Figure '7 into latching engagement with the latch 94. A suitable trigger housing I I8 is secured to the tubular body 52. 5

Within the tubular body 52 above the clutchsleeve and secured to the former by a screw 8 is a guide bushing I through which the upper portion of the hammer passes. The upper end of the hammer is adapted to move the operating rod I22 of a dial indicator I24, This action occurs on upward movement of the pistons in cylinders and 58. The indicator is removably secured to the upper end of the tubular member 52 by means of a thumb screw (see Figure 2).

In Figures 1 to.5, inclusive, are illustrated the means for controlling air flow to actuate the pistons oi the hardness testing machine. Fixed to the bracket I4 is a valve-body I which has passages I82 and I84 therein connected by flexible air lines I88 and I88, respectively, to the fourway valve 24. Passage I32 in the valve body I30 branches to form two passages I40 and I42. An adjustable needle valve I44 controls air flow through passage I40 and an adjustable needle valve I48 controls flow through passage I42. The passage I40 is connected by pipe 34 to the upper end of cylinder 80, while passage I42 is connected by flexible air line 82 to the upper end of the small cylinder 58. The respective needle valves are so adjusted that the piston 80 in its downward movement in small cylinder 58 lags behind the piston in the cylinder 80. The passage I34 in the valve-body I80 also has two branches I48 and I50 having adjustable needle valves I52 and I54, respectively, therein for controlling air flow therethrou'gh. Branch-passage I48 is connected by the pipe 38 to the lower end of cylinder 30, while branch-passage I50 is connected by the flexible air line 84 to the lower end of small cylinder 58.

Air for operating the pistons is supplied to the inlet of the four-way valve 24 from air line I80 leading to any suitable source of air under pressure. An air line I82 branching from the line I80 leads to the foot-operated valve 28. An air line I84 leads from the foot-operated valve 28 to the tour-way valve 24 for operating a piston I88 therein, which in turn operates a pivoted arm I88 of the four-way valve for operating poppet valves of the four-way valve for controlling the flow of air to the pistons 30 and 58. Two of the operating rods for the poppet valves are shown at "0 and I12. When the foot pedal I14 of the foot-operated valve 28 is depressed the piston I88 of tour-way valve 24 is moved in one direction to permit air from the pressure supply line I80 to pass by way of the four-way valve 24, air line I38, passage I32 in valve-body I30, branch passages I40 and I42, pipe 34 and flexible air line 82 tothe upper ends of cylinders 30 and 58 thus pushing down the pistons therein. As the pistons move down air from below the pistons in cylinders 30 and 58 passes by way of pipe 38, air line 84, branch passages, I48 and I50, passage I34, and flexible air line I38 to the four-way valve 24 where it is exhausted to the atmosphere. Releasing of the foot pedal of valve 28 causes movement of piston I88 of the four-way valve 24 to thereby actuate the valve to cause air under pressure to flow from the source of supply through flexible air line I38 to passage I34 in valve-body I30, needle valve controlled branch passages I48 and I50, pipe 38 and air line 64 to the bottoms of cylinders 30 and 58 to cause upward movement of the pistons in these cylinders. Air from above these pistons travels back through the pipe 34, air line 82, branch passages I40 and I42 controlled by needle valves, air passage I32 in valvebody I30 and flexible air line I38 to the four-way valve where it is exhausted to the atmosphere. Any four-way valve or valve capable of controlling a double acting air cylinder may be employed. In place of being operated by the pneumatic means illustrated, the four-way valve may also be operated electrically or by a cam operated, variable speed, toggle pilot valve, or by other suitable means.

The operation of the apparatus in testing the hardness of materials will now be summarized. The part to be tested is laid'on the anvil II. The foot pedal of valve 28 is depressed to actuate the up by spring 48. Lagging slightly behind the large piston, due to suitable adjustment of the needle valves I44 and I46, the small piston 60 in cylinder 58 also moves downward. The needle valves are so adjusted that the hammer is not released until after the work is clamped to the anvil. By means of rod 86 connected to piston 60, the pin 68 is moved downward. Pin 68 in turn moves the clutch sleeve 14 downward within the tubular body 52, the pin moving in the elongated slot I in the tubular body 52. During most of the downward movement of the clutch sleeve 14 the hammer 98 is held stationary by the pilot sleeve 92, which in turn is held by the dog III] of the trigger I06 pivoted to the tubular body, the spring I I4 biasing the dog into latching engagement with the latch 94 on the pilot sleeve. The sleeve 18 travels downward with the clutch sleeve 14. Just before the clutch sleeve .14 reaches the bottom of its travel. the upper end of the slot 84 in sleeve 18 contacts the upper end of latch 94. Sleeve 18 now remains stationary while clutch sleeve 14 travels approximately .020" farther down. During this short travel the steel balls 82 are held stationary by the sleeve 18 and as the outwardly tapered surface 16 of clutchsleeve 14 travels downward the jamming contact between the steel balls and the hammer 98 is broken. The upper end. of the slot 11 in clutch sleeve 14 now presses against the finger H2 at the upper end of the trigger I06 causing the trigger to move outward about its pivot I08, thereby releasing latch 94. When the latch is thus released the hammer 98 and pilot sleeve 91 drop by means of gravity and the diamond point of the hammer strikes the part to be tested causing the hammer to rebound upward a distance dependent on the hardness of the material. The greater the hardness the greater the rebound. Pilot sleeve travels downward a short distance farther than the hammer in its downward movement. The pilot sleeve moves down until it hits the flange I04 of ring I02 which is threaded on the lower end of sleeve 18. The sleeve 18 which has been held up by the friction spring 86 is forced downward by the blow to its original position relative to the clutch-sleeve 14. This allows the balls 82 to drop against the cone surface 16. Al-

though the hammer can still travel upward on its rebound the instant it reaches the'top of its travel the balls jam and prevent the hammer from dropping down.. The operator 'now releases the foot pedal ofthe valve 26 and air now enters the bottomends of cylinders 30 and 58 (through the action of the four-way valve l4) and the pistons 32 and 60 are raised to their original up position shown in Figure 3. Upward movement of piston 32 unclamps the part being tested. Upward movement of piston 60 raises clutch sleeve 14, sleeve 18 and pilot sleeve 92. As soon as the clutch sleeve raises from the upper finger of the trigger, the spring H4 biases -the trigger into latching engagement with the latch 94 on the pilot sleeve 92. The hammer-98 is held by the cone clutch and it raises with the clutch sleeve 14. Contacting the rod I22, it transfers the rebound. height to the dial indicator I24. This reading is held until the next piece is tested or until the hammer is dropped without a piece in the machine. In this latter case there will be no rebound and no reading will be recorded. The needle of the dial indicator will then rest at zero.

It will be noted that both hands ofthe opera.- tor are free at all times to load and unload parts being tested. The machine is rapidin operation and gives most accurate readings.

Various changes and modifications may be made in the embodiment of my invention illustrated and described herein without departing from the principles of my invention.

I claim: I 1. In a hardness testing machine, a base, an anvil supported thereby, a'post rising from said base, a bracket adjustably mounted on the post for adapting the machine to work of different sizes a hollowcolumn carried by the bracket, a first fluid pressure cylinder carried by the hollow column, a first piston in said cylinder, a sleeve in the hollow column below the cylinder, a piston rod having one end fixed to the piston and its other end extending into said sleeve, a spring connection between the sleeve and rod forming a resilient connection between the two, a tubular member supported from the sleeve for ,movement therewith and adapted to be moved thereby to clamp work to be tested to the anvil, a releasable hammer within the tubular member, a second fluid pressure cylinder carried by the said tubular member and movable thereby, a second piston in said second cylinder, means actuated by the second piston for releasing the hammer whereby the same may fall, means for controllin flow of pressure fluid to the two cylinders so that thesecond piston is actuated to release the hammer after the work has been clamped to the anvil, the hammer then falling and striking the work and rebounding to a height dependent on the hardness of the work, and means for measuring the amount of rebound of the hammer.

and its other end extending into saidsleeve, a,

spring between the sleeve and rod forming a resilient connection between the two, a tubular member movable with the sleeve and adapted upon downward movement of the first piston to clamp work to be testedto the anvil, a releasable hammer within the tubular member, a second fluid pressure cylinder carried by the said tubular member and movable thereby, a second piston in said second cylinder, means actuated by downward movement of the second piston for releasing the hammer whereby the same may fall by gravity, means includin adjustable needle valves for controlling flow of pressure fiuid to the tw cylinders so that the second piston is actuated 'to release the hammer after the work has been clamped to the anvil, the hammer then falling and striking the work and rebounding'to a height dependent on the hardness of the work, means for holding the hammer at its limit of rebound, and means for measuring the amount of rebound of the hammer upon upward movement of the two pistons.

3. In a, hardness testing macbine,'a work support, a tubular member, a releasable hammer.

is actuated to'release the hammer after the work has been clamped to the support, the hammer 'then falling "and striking the work and reboundin to a height dependent on the hardness of the work, and means for measuring the amount of rebound of the hammer..

4. In a hardness testing machine of the type in which the hardness of material is determined by theheight to which a falling hammer will rebound upon striking the work to be tested, the combination which includes, a work support, a

movable tubular member above the work support,

a releasable hammer within said tubular member, pneumatic means for moving the tubular member to clamp thep'a'rt being tested to the worksu p man' air cylinder carried by the tubuark-reenter and movable thereby, a piston in said cylinder, means-actuated by the piston for releasing the hammer,"'and means for controlling 'flo'w'of air' to'said pneumatic means and to said air cylinder to actuate the piston to operate automatically said hammer releasing means only after 'said pneumatic means has moved the tubular member into work clamping position, said hammer when released falling and striking the work and then rebounding to a height dependent on the hardness of the material being tested.

DOUGLAS E. MICK.

REFERENCES CITED The following references are of record in the file of this patent!v UNlTED STATES PATENTS Number Name Date 962,790 Shore June 28, 1910 1,154,663 Shore Sept. 28, 1915 1,444,606 Hermann Feb, 6, 1923 FOREIGN PATENTS Number Country Date Great Britain Nov. 14, 1927 

